Plugs for key operated lock mechanisms

ABSTRACT

A KEY OPERATED PLUG ASSEMBLY FOR A LOCKING MECHANISM THE PLUG BEING ADAPTED TO BE PIVOTALLY MOUNTED IN A BODY, WHICH PLUG COMPRISES BODY ENGAGING MEANS TO PREVENT PIVOTAL MOVEMENT OF THE PLUG WITHIN THE BODY, THE BODY ENGAGING MEANS BEING RENDERED INOPERATIVE BY THE INSERTION INTO THE PLUG OF AN APPROPRIATE KEY, A FACE ELEMENT HAVING THEREIN A KEY RECEIVING OPENING AND BEING CONNECTED TO THE REMAINDER OF THE PLUG BY MEANS OF A COLLAPSIBLE CONNECTION, THE ARRANGEMENT BEING SUCH THAT WHEN MORE THAN A PREDETERMINED FORCE IS APPLIED TO THE FACE ELEMENT THE COLLAPSIBLE CONNECTION FAILS SO THAT THE FACE ELEMENT ROTATES RELATIVE TO THE REMAINDER OF THE PLUG.

United States Patent 72] inventor Daniel Victor Berry Braeknell, England [2]] Appl. No, 5,219 [22] Filed Jan. 23, 1970 [45] Patented June 28, 197 I [73 Assignee to lngersoll Locks Limited, London, England [32] Priority Jan. 24, i969 Great Britain 4300/69 [54] PLUGS FOR KEY OPERATED LOCK 38 (A), 38 (B), 38 (C), 39, 51, 52, 364 (R), 365, 366, 367, 375, 386, 383, M9, 422, 349, 355, 363,

[56] References Cited UNITED STATES PATENTS 1,662,487 70/422 3/l928 Briggs Primary Examiner-Ian A. Calvert Assistant ExaminerEdward J. McCarthy Attorney-Edwin E. Greigg ABSTRACT: A key operated plug assembly for a locking mechanism the plug being adapted to be pivotally mounted in a body, which plug comprises body engaging means to prevent pivotal movement of the plug within the body, the body engaging means being rendered inoperative by the insertion into the plug of an appropriate key, a face element having therein a key receiving opening and being connected to the remainder of the plug by means of a collapsible connection, the arrangement being such that when more than a predetermined force is applied to the face element the collapsible connection fails so that the face element rotates relative to the remainder of the plug.

PLUGS FOR KEY OPERATED LOCK MECHANISMS This invention relates to plugs for key operated lock mechanisms of the type in which the plug is pivotable within a body, the plug being normally locked against pivotal movement but unlocked as a result of the insertion therein of an appropriate key to permit pivotting of the plug and hence withdrawal ofa locking element ofthe lock mechanism.

According to the present invention there is provided key operated plug means for a lock mechanism, the plug being adapted to be pivotally mounted within a body, which plug means comprises body engaging means to prevent said pivotal movement of the plug means within the body, said body engaging means being rendered inoperative by the insertion in the plug means of an appropriate key, a face element having therein a key receiving opening and being connected to the remainder of the plug means by means of a collapsible connection, the arrangement being such that when more than a predetermined force is applied to the face element the collapsible connection fails so that the face element rotates relative to the remainder of the plug.

The plug means may include a plurality of pivotable levers, the levers being pivotable individually to positions determined by the profile of the key, the body engaging means being arranged to prevent pivotal movement of the plug within the body until all of said levers are in said predetermined positions as a result of the insertion of the appropriate key. The body engaging means may comprise a talon pivotally mounted in the plug and normally biassed to a position projecting beyond the periphery of the plug and adapted to engage with a recess in the body when the plug is mounted therein. The talon may be pivotable, as a result of pivotal movement of the plug, out of said recess to be at least partially accommodated in a further recess formed by a notch formed in the periphery of each of said plurality of levers when said notches are aligned as a result of the levers being in the predetermined positions.

The levers may be pivotally mounted on a shaft secured to the plug means, the talon being pivotally mounted on a second shaft secured to the plug means, the face element being secured to the remainder of the plug means through the shafts, the connection of the face element to the shafts being such as to collapse when more than a predetermined force is applied to the face element. The ends of the shaft may be secured to the face element in shallow recesses and the ends of the shaft may be chamfered to facilitate failure at this point.

Following is a description by way of example and with reference to the accompanying drawings of various embodiments in accordance with the present invention.

in the drawings:

FIG. 1 is a section through a padlock in accordance with the present invention.

FIG. 2 is a plan view of the underside of the padlock of FIG. 1.

FIG. 3 is a section on X-X of FIG. 1.

FIG. 4 is a detail ofFlG. 1.

FIG. 5 is a detail showing an alternative embodiment of the invention.

FIG. 6 is a detail showing another embodiment of the invention.

FIG. 7 is a detail showing a further embodiment of the invention.

The padlock 10 has a main body 11 of substantially elliptical cross section which is built up of a number of elliptical lamina plates 12 made of steel, each plate having a nitridehardened surface. A main bore 13 is formed in one end face of the body 11, the polar axis of the bore 13 being coaxial with the polar axis of the body 11, said bore 13 having a longitudinal recess 14 formed in the wall thereof. Two spaced substantially cylindrical secondary bores 15, each adapted to receive a limb 16 of a removable shackle 17 extend partially through the body 11 from the other end face of the body, the secondary bores being parallel to the polar axis of the body and spaced towards the periphery of the body along the major axis of the ellipse.

A transverse bore 18 extends within the body between each of the two secondary bores 15 and the main bore 13. Each transverse bore 18 accommodates a locking ball 20 within said transverse bores 18 and movable between a first locking portion in which the ball 20 projects into the secondary bore 15 and a second free position in which the ball 20 does not project into said secondary bore 15.

Each secondary bore 15 is adapted to accommodate a limb l6 ofa U-shaped shackle I7, which is of circular cross section has a pair of spaced limbs one of which is longer than the other to locate the shackle I7 relative to the padlock body when each limb i6 is entered into said secondary bores 15. An arcuate recess 21 is formed in the inner surface of each of the limbs 16, the recesses 2| lying substantially in the same plane so that when the shackle 17 is fully inserted in the secondary bores 15, the recesses 21 are aligned with the transverse bores 18 the arrangement being such that with each ball 20 positively located in said first position, the ball 20 enters into the associated recess 2! in the limbs 16 of the shackle l7 and are jammed between the surface defining the recess 21 in each of limbs 16 and the body ll thus serving to restrain removal of the shackle 17 from the body 11 of the padlock 10.

The main bore 13 of the padlock accommodates a locking plug assembly 30 which latter is a composite assembly comprising three contiguous elements, namely cam means 31 for positively locating said locking balls 20 into said first position constituting the innermost portion of the assembly, body engaging means 32 to prevent pivotal movement of said plug assembly 30 relative to the padlock body ll constituting the central or intermediate portion of the assembly and a discshaped face piece 33 having a convex external surface 34 which constitutes the outer portion of the assembly.

The cam means 31 provided at the inner end of the plug assembly 30 is disposed adjacent the transverse bores 18 in the body ll. That portion 35 of the cam means adjacent the said intermediate portion of the assembly comprises a generally cylindrical portion extending axially of the assembly approximately halfthe length of the total extent of the cam means 31. This cylindrical portion 35 has an annular recess 36 in its circumferential surface which accommodates an O-ring 37 to effeet a seal between said cylindrical portion 35 and the wall defining the main bore 13 within the padlock body 11. The remainder of the cam means comprises a cylindrical portion 38 of reduced cross section which is flared at 39 towards the inner extremity of the plug assembly 30 to terminate in an annular rib or projection 40. A pair of spaced parallel segments are removed from the reduced and flared portion 38, 39 respectively of the inner extremity of the plug assembly 30 so as to provide a pair of plane parallel faces 41 parallel to the longitudinal axis of the plug assembly 30 each constituting the heel of the cam means 31, the arrangement being such that on locating the plug assembly 30 relative to the padlock body 11 so that the plane faces 4] of the inner extremity of the plug assembly 30 are disposed adjacent the transverse bores 18 in the padlock body ll, the locking balls 20 can fall back within the transverse bores 18 to a second position in which the balls 20 are housed by the padlock body ll inwardly of the secondary bores 15 to permit the removal and insertion of the shackle 17. On rotating the plug assembly 30 through an angle of substantially the curved portions of the cam means 31 are caused to contact the balls 20 and to urge the same outwardly with respect to the main bore 13 of the padlock body ii to their first locking position in which the shackle 17 may be locked into position or in which complete entry of the shackle limbs 16 into the secondary bores 15 is prevented. The main bore 13 in the padlock body 11 is contoured to provide recesses (not shown) at its inner end so that with the plug assembly 30 disposed in the locking position with the balls 20 engaging the shackle recesses 21, the said cam surfaces enter said recesses at the end of the bore 13 to prevent withdrawal ofthe plug assembly 30 from the padlock body ll.

The intermediate portion of the plug assembly comprises first and second longitudinally disposed spaced rods 45 and 46 respectively extending from the substantial circular end 35 of the cam means 31 to engage with the disc-shaped face piece 33. The outer end 47, 47' of each rod is chamfered and is accommodated within a circular recess 48 in the inner surface 49 of the face piece 33 each recess being substantially 0.0l inch in depth, thus constituting a collapsible connection, the arrangement being such that when a torque is applied to said face piece 33 greater than a predetermined torque, the connection will fail by the ends of the rods 45, 46 leaving their recesses 47, 47 thereby permitting the face piece 33 to rotate relative to the rest of the plug assembly 30. The spaced rods 45, 46 define two points on a cord plane within the generally circular plug assembly 30, thus dividing the generally cylindrical arrangement constituting the body engaging means 32 into a major segment and a minor segment.

Each of the longitudinal rods 45, 46 serves to support five divider plates 50 at spaced intervals along each rod and with the plates 50 located in planes substantially perpendicular to the longitudinal axis of the plug. The dividers are separated one from each other by a spacer 51, five spacers 51 being provided, one between each pair of dividers 50 and one between the outermost divider 50 and face piece 33, the complete assembly being made up from a zinc based alloy casting which is appropriately shaped to provide the dividers 50 and spacers 51.

Between each divider 50 there is located a pair of lever members 60 pivoted in a scissor configuration about rods 45, which is hereinafter referred to as the lever pivot 45 each lever of said pair being disposed on opposite sides of the spacer 51 associated therewith. Each pair of levers 60 has disposed between them a spacer 51 and each pair of levers 60 is arranged so that each lever is mounted about the lever pivot 45 for movement in a sense opposite to the other lever of the pair. Each lever 60 is spring biassed by means of spring 61 to a datum position and is provided with a key engaging portion 62 which together with the corresponding portion of the other levers defines a central keyway extending within the center of the plug assembly 30, the arrangement being such that on passing an appropriate key into said central keyway, the levers are moved against their spring loading to adopt an operative position.

The levers 60 are substantially hooked shaped about the central keyway and extend about a major part of the circle defining the cross section of the body engaging means 32.

The dividers 50 and spacers 51 are each cut away at a point substantially opposite the lever pivot 45 to provide a recess 65 for the purpose hereinafter described. The levers 60 are each provided with a notch 66 in the peripheral edge which extends within said recess 65, the arrangement being such that with the key inserted, the notches 66 are all aligned as a result of movement of levers 60 to cooperate with said key to define a longitudinal groove 67 substantially parallel to the axis of the plug assembly 30 and to the axis of the second rod 46 which is spaced circumferentially of the said recess 65 in the dividers 50 and spacers 51 constituting the support assembly for the body engaging means 32. The alignment of the notches 66 in the periphery of the levers 60 is such that on withdrawing the key, the levers 60 return to their datum position under the influence of their spring loading about the lever pivot 45 with the result that the notches 66 are randomly distributed within said recess 65 in the support assembly.

The second longitudinal spaced rod 46 constitutes a pivot for a talon 70 comprising a pair of spaced arcuate arms 71 terminating in a thickened portion 72 with an inwardly projecting longitudinal ridge 73 which is adapted, when the key is inserted within the keyway, to enter the groove 67 defined by the aligned notches 66 in the peripheries of the levers 60. The thickened portion 72 of talon 70 has an upstanding pin 74 extending inwardly of the inner edge 75 of the talon 70.

The outer end 80 of the cam means 31 is cut away at 81 adjacent said recess 65 to accommodate said pin 74 and a spring steel wire spring 82 is disposed across the entrance to the recess 81 so formed so that the talon 70 is spring-loaded outwardly of the plug assembly 30 by means of said spring 82 coacting against said pin 74 to urge the longitudinal ridge 73 of the talon projection out ofthe groove 67 defined by the plurality of aligned notches 66 in the peripheral edges of the levers 60. The plug assembly 30 is accommodated within the main bore 13 of the padlock body 11 and in a locking attitude for pivotal movement therein with the cam surfaces of the cam means 31 urging the locking balls 20 to the first locking position, the talon ridge 73 is biassed out of said groove 67 and at least part of said talon is disposed within the recess 14 in the wall of the main bore 13 of the padlock body 11.

The plug assembly 30 is located within the main bore 13 of the padlock body 11 and is retained therein by means ofa face plate which is rivetted to the body 11 by rivets 91 to cover the end piece 33 and to maintain the plug assembly 30 within its bore 13. The face plate 90 is provided with a butterfly 92 opening to permit access to the keyway and to permit the key to be turned from a first position in which the plane of the key is substantially in the major axis of the elliptical cross section of the padlock body to a second position which is at an angle of substantially 90 to the first position until the key is located substantially within the minor axis of the elliptical cross section of the padlock body.

Removal of the key when in the first position permits each lever 60 to return to its datum position under its individual spring loading, thereby causing the peripheral notch 66 in each lever to adopt a random position one with respect to the other thus preventing movement of the talon 70 into the plug itself and stopping rotation of the plug. In this attitude with the shackle in its locking position, the balls are disposed within the arcuate notches in the limbs of the shackle and serve to lock in these notches with the body of the padlock thus preventing withdrawal of the shackle from the secondary bores.

On entering the key into the key opening, the key will abut the key engaging portion 62 of each lever 60 and move each lever 60 against its spring bias so that with the key fully home within the keyway, the peripheral notch 66 in each lever 60 aligns with the notches 66 in the other levers 60 to define a longitudinal groove 67. The application of a turning motion to the key will cause the external surface of the talon 70 to bear against the internal wall of the main bore 13 of the padlock body to urge the talon 70 inwardly of the plug assembly 30 until the pin 74 abuts the spring wire 82 disposed across the top of the recess 81. Continued turning movement of the key produces continued turning movement of the plug assembly 30 and urges the talon 70 inwardly until the talon ridge 73 enters the said longitudinal groove 67 against the spring loading applied to the pin 74 of the talon 70 by means of said spring wire 82. When the key has been turned through an angle of substantially 90, the parallel plane faces 41 of the cam surface are adjacent the junction of the main bore 13 with the transverse bores 18 thereby permitting the balls 20 to adopt a second unlocked position and to permit withdrawal of the shackle 17 from said secondary bores 15. Reinsertion of the shackle 17 and turning of the key to the first position produces a reverse procedure in which the balls 20 are urged to a first locking position by means of the cam surfaces now in conjunction with the inner ends of each transverse bore 18 and the talon 70 is correspondingly urged into the adjacent recess 14 in the internal wall of the padlock body 11. Withdrawal of the key permits each lever 60 to return under its individual spring loading to its datum position thus preventing entry of the talon 70 into the body of the plug assembly 30 and preventing rotation of the plug assembly 30 within the body 11 of the padlock 10.

Where an attempt is made to force the padlock by insertion of a sharp instrument into the key opening in the face piece 33 of the plug assembly 30, the application of considerable torque in an attempt to force the lock by causing failure of the talon 70 and/or levers 60 results in failure of the connection between the face piece 33 and the remainder of the plug assembly 30 itself when the torque applied to the face piece 33 with respect to the body of the plug exceeds the predetermined amount. The failure occurs as the rod ends 47, 47 are forced out of the shallow recesses 48 thus permitting the face piece 33 to rotate without moving the remainder of the plug assembly 30.

In alternative embodiments of the invention it will be appreciated that the collapsible connection may be formed in a number of ways. For instance the outer ends of the pair of spaced parallel rods extending through the intermediate portion of the plug may be provided with a weakened portion towards the end which extends into the appropriate recess in the face piece so that a portion of each rod will shear on the application of excessive torque between the face piece and the rods.

In another embodiment, (see FIG. 5) the outer end 47 of each rod will terminate in an outwardly extending pin I00 of substantially reduced diameter compared with the diameter of the rod which is accommodated within a cooperating recess 48 within the face piece the arrangement beingsuch that the application of abnormal torque to the face piece 33 produces shearing of the pin 100 to permit rotation of the face piece 33 with respect to the intermediate portion of the plug assembly 30.

In a further embodiment (FIG. 6), the outer end 47 of the rod may have spaced inwardly of the outer extremity 101 a substantially reduced portion 102. The extremity of the rod is located in a recess in the face piece in the manner described above, the arrangement being such that on the application of abnormal torque to the face piece, failure of the reduced portion of the rod severs the same, to permit the face piece to rotate with respect to the intermediate portion of the plug.

In another alternative embodiment (FIG. 7), the outer end 47 of each rod may be rounded at 104 instead of chamfered and accommodated within a cooperating recess, the failure function of such a collapsible connection being substantially as described above.

It will be appreciated that although the invention has been specifically described as applied to a padlock that this invention can be applied to any form of lock mechanism having a plug pivotable within a body.

lclaim:

l. A lock assembly, including a locking key operated plug mechanism pivotally mounted in a lock body having a face element and including a notch means, said plug mechanism comprising body engaging means to prevent pivoting movement of the plug within the body, said body engaging means being rendered operative by the insertion into the plug mechanism of an appropriate key, the face element of said body engaging means having therein a key receiving opening and connected to the remainder of the plug by means of a collapsible connection, said collapsible connection being adapted to fail when more than a predetermined force is applied to said face element, whereupon the face element rotates relative to the remainder of the plug.

2. An assembly as claimed in claim 1, wherein the plug mechanism includes a plurality of pivotable levers having notch means, the levers being pivotable individually to posi tions determined by the profile of the key, the body engaging means being arranged to prevent pivotal motion of the plug within the body until all of said levers are in said predetermined positions as a result of the insertion of the appropriate key.

3. An assembly as claimed in claim 2, wherein the body engaging means comprises a talon pivotally mounted in the plug mechanism and normally biased to a position projecting beyond the periphery of the plug and further adapted to engage with the notch means in the body when the plug is mounted therein.

4. An assembly as claimed in claim 3, wherein the talon is pivotable out of said notch means in said body to be at least partially accommodated in the notch means in said plurality of levers when the last-named notches are aligned as a result of the levers bein in the said predetermined sitions. notches 5. An assem ly as claimed in claim 4, w ereln the levers are pivotally mounted on a first shaft secured to the plug means, the talon being pivotally mounted on a second shaft secured to the plug means, the face element being secured to the remainder of the plug means through the shafts, the connection of the face elements with the shafts being such as to collapse when more than a predetermined force is applied to the face element.

6. An assembly as claimed in claim 5, wherein the shafts include terminal portions which are arranged to be received in recesses in the face element, said terminal portions of the shafts constructed to be disengaged from said recesses when application of excessive force is applied to said face element.

7. An assembly as claimed in claim 5, wherein said terminal portions of the shafts include frangible means.

8. An assembly as claimed in claim I, wherein the body within which the locking key operated plug mechanism is mounted is a bore in a padlock structure provided with a staple means.

9. An assembly as claimed in claim 8, wherein first means adjacent to the upper extremity of said plug is arranged for cooperation with other means to either lock the staple means relative to the body or permit its release therefrom.

10. An assembly as claimed in claim 9, wherein said first means includes cam means and the staple means include confronting depressions.

II. An assembly as claimed in claim 10, wherein ball means are interposed between the cam means and the depressions in said staple means.

12. An assembly as claimed in claim 8, wherein the plug mechanism includes seal means for engagement with said bore.

13. An assembly as claimed in claim 10, wherein the first and second shafts extend through the plug assembly from adjacent the cam means to the face element.

14. An assembly as claimed in claim 9, wherein the recesses are substantially 0.0 l 5 inch in depth.

15. An assembly as claimed in claim 5, wherein the first and second shafts divide the plug assembly into major and minor segments.

16. An assembly as claimed in claim 15, wherein the said shafts are arranged to support divider plates.

17. An assembly as claimed in claim 16, wherein the divider plates are perpendicular to the axis of the plug assembly.

18. An assembly as claimed in claim 17, wherein the divider plates are positioned in spaced relation by spacer means.

19. An assembly as claimed in claim 16, wherein the pivotal levers pivot about at least one shaft and are interposed between the divider plates. 

